Method of inhibiting discoloration of color photographic layers containing dye images and resulting photographic products



United States Patent O v 3,157,504 ME'I'HGD F INHIBETENG DISQULQRATZQN GF COLOR PHGTGGEHC LAYERS CONTAG DYE IMAGE-SAND RESULTING PHQTGGRAPH- 1C PRODUCTS Charleston C. Bard, Rochester, N.Y., assig'nor to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey No Drawing. Filed Apr. 2, 1962, Ser. No. 184,494 7 Claims. (Cl. 96-61) This invention relates to color photography and more particularly to methods for preventing discoloration of photographic dye images. The invention also includes photographic layers or elements stabilized against discoloration according to the new methods.

Photographic color images can be produced by a variety of processes. Perhaps the most common involves the formation of the desired color record by coupling between one or more color couplers and the oxidation products of an ordinary photographic color developing agent, such as a phenylened-iamine. The color coupler in such processes can be incorporated either within the photographic element itself, or within the color developer solution. Another method of producing a color record involves the use of the Well known dye bleach process, wherein a uniformly dyed layer is selectively bleached in accordance with a silver record produced through conventional photographic evelopment- Bleaching occurs at the site of formation of the silver image. Still another means of producing a photographic color image is through a diffusion transfer process which uses a dye developer to effect photographic development and to produce a didusible dye, which then migrates imagewise to a receiving surface. The present invention provides a means of stabilizing all of these types of photographic dye images, although it is particularly useful in preserving dye images which have been produced by the conventional process of color development using a color developer containing the color-forming compound, or coupler. This latter process is a reversal type of process wherein the color development is preceded by a conventional black-and-white development operation which produces a negative silver image. After negative development, there is one or more exposures followed by color development in a developer containing the desired colorforming compound, or coupler.

It is, therefore, an object of the present invention to provide an improved method for preventing the discoloration or decomposition of photographic layers containing dye images subject to fading, or print-out under the influence of actinic radiation. it is a further object to provide photographic color materials, including films, transparencies, or prints which have been stabilized by treatment with particular stabilizing compounds. Other objects will become apparent from a consideration of the following description and examples.

The foregoing objects are accomplished according to my invention by bathing the finished photographic record (i.e., after complete color-development, bleaching, fixation, etc.) with an aqueous solution'containing a watersoluble a-glucoheptonate salt, or the acid, per'se. These stabilizing compounds can be represented by the following general formula:

wherein M represents a hydrogen atom or a water-solubilizing cation, such as ammonium, alkali metal (e.g., sodium, potassium, etc.), or organic ammonium (e.g., triethanol ammonium, pyridiniurn, etc.). These compounds may be used in the form of their hydrate derivatives, since 3,157,504 Patented Nov. 17, 19%.-

ice

they are rather hydrogroscopic, or tend to spontaneously absorb water from ambient surroundings. A particularly useful treating agent is sodium a-glucoheptonate dihydra'te.

The system of three-color photography suggested by Fischer in U.S. Patent 1,055,155, issued March 4, 1913, forms the basis for a number of color photographic processes and products. In one embodiment, this process involves the incorporation of different color-iorrnin g coupler compounds in each of three superposed differently colorsensitized (red, green and blue) silver halide emulsion layers. Each of the three couplers is capable of producing a color complementary to the sensitivity of the layer in which it is incorporated by reaction with the oxidation products of certain types of photographic developing agents. In this way a developed silver image and a colored dye image are formed simultaneously in each of the three superposed emulsion layers. The silver images and residual undeveloped silver halide may then be removed from the multilayer photographic element by bleaching, fixing and washing according to now well-known methods. Alternatively, the color-forming couplers can be incorporated in the developer rather than in the emulsion layers as disclosed in Fischer U.S. Patent 1,102,028, issued June 30, 1914.

The couplers suggested by Fischer containing phenolic hydroxyl, or ketomethylene groups, react with the oxidation products of aromatic amine developing agents during photographic development to form indophenol, indamine, indoaniline or azomethine (including quinone-imine) dyes. Dyes produced by developing with aminophenols in the presence of a phenol or naphthol coupler are indophenol dyes, those produced by developing with a phenylenediamine type developer in the presence of an aniline coupler, phenol or naphthol couplers, or reactive methylene compounds are indamine, indoaniline and azomethine dyes, respectively. Azomethine and indoaniline dyes are present in many of the processed photographic color products produced by current photographic processes.

While the process of Fischer U.S. Patent 1,055,155 in which the color-forming couplers are incorporated in the emulsion layers is theoretically feasible, it has not been entirely successful due to the tendency of the couplers to diffuse out of their respective emulsion layers during coating, or processing. For this reason, it has been proposed to react the coupler molecules with high molecular weight, or colloidal, bodies torender the couplers non-diffusing in gelatin. or other colloidal media. It has also been proposed to mix the couplers with a Water-insoluble colloid, such as a natural or synthetic resin, or a cellulose ester, and to subsequently disperse this mixture in the gelatin emulsion. Methods of this type are disclosed in Martinez U.S. Patent 2,269,158, issued January 6, 1942, and in Mannes and Godowsky U.S. Patents 2,304,939 and 2,304,940, issued December 15, 1942. These patents also disclose specific couplers adapted to be dispersed in emulsionlayers as just described. Other couplers are disclosed in Jelley et al. U.S. Patent 2,322,027, issued. June 15, 1943, Fierke et a1. U.S. Patent 2,801,171, issued July 30, 1957, and in Porter et al. U.S. Patent 2,369,489, issued February 13, 1945, as well'as in numerous other patents, which use a water-insoluble, crystalloidal, high-boiling solventfor the color. coupler.

Specific couplers useful'in photographic color processes in which the couplers are not dispersed in a Water immiscible solvent are disclosed in the following representative references: Mannes and Godowsky U.S. Patent 2,039,730,

issued May 5, 1936, hydroxy diphenyl couplers which form blue or blue-green dyes; Mannes and Godowslty' U.S. Patent 2,108,602, issued February 15, 1938, acetoacetamides and cyanoacetamides, containing reactive methylene groups, which form yellow dyes; Mannes and Godowsky US. Patent 2,115,394, issued April 26, 1938, organic compounds containing the cyanoacetyl group which form red and magenta dyes; and Richey andJensen US. patent application Serial No, 670,900, filed July 10,

' .1957, water soluble cyan, magenta and ellow 'dye-form ing couplers. 7

The developing agents useful for color development of f emulsion layers containing couplers of the'type described above or for the development of emulsion layers in the presence of these couplers include the Well-known primary aromatic amine silver halide developing agents, such as the phenylenediamines, including the N-alkylphenylenediamines and N-alkyltolylenediamines. These developing agents are usually used in the salt form, such as the hyd'rochloride, or sulfate, Whichfis more stable than the amine. The p-aminophenols and their substitution products can also be used where the aminogroup is unsubstituted. The N-alkylsulfonamidoalkyl-p-phenylenediamine agents of Weissberger U.S. Patent 2,193,015, issued March 12, 1940, are also very useful. All of the developing agents have an unsubstituted amino group which enables the oxidation products of the developer to couple with the color-forming compounds to form a dye image.

Many indophenol, indamine, indoaniline and azomethine dyes are relatively unstable to light with the result that into the photographic layers to inhibit fading ofthe dye images or print-out of any residual dye-forming coupler dye images in finished commercial colorpictures have a tendency to fade, especially when subjected to intense i1- lumination for extended periods of time. This isrtrue Whether the isource of illumination is sunlight, tungsten, or fluorescent lamps. The cyan dyes are generally relatively less susceptible to fading than the other dyes com monly usedin color photography. In processes in which the couplers are incorporated in the emulsion layers or in plain gelatin layers in the film, further difliculty is caused by residual unused coupler which tends to print-out as a stain, usually a yellow stain, under the influence of light especially inrthe high light areas of the picture. Magenta dye-forming couplersare generally more susceptible to print-out than others. 7

. In general, two methodshave been suggested to prevent discoloration of photographic layers One of these comprises overcoating the photographic layer to be protected with a substance capable of absorbing ultraviolet light. Methods of this type are disclosed in Salminen and Allen U.S. Patent 2,632,70l,' issued March '24, 1953, and Edgerton and Staud U.S. Patent 2,747,996, issued May 29, 1956.

The other method referred to above comprises treatment of photographic layers containing dye images with certain chemical compounds, particularly organic reducing agents or antioxidants, in order to stabilize the dye images and V any residual coupler in the photographic layer. 'Methods of this type are disclosed in Vittum U.S. Patent2,384,658, issued September 11, 1955, and Macke'y U.S. Patent 2,579,435, issued December 18, 1951. Methods of .the latter type have been found to be mostly empirical. For example, although the reducing agents of the Vittum pat ent are useful, others of similar reducing properties have 7 no effect on the stability of photographic dye images;

Further, many reducing compounds Whichmight suggest themselves as stabilizing agents not only have no stabilizingproperties but actually cause stain. or destruction of.

dye images in photographic layers. It has, therefore,

been dificultto find compounds having appreciable dye stabilizing or anti-print-o'ut properties which arealso free from other undesirable characteristics. Therefore; a1-

' though the above and other methods have been suggested therein. In practice, the photographic element or layer containing the dye image, but substantially free from de-' veloped silver, silver halide and other soluble salts, is im-.

mersed in a bath comprising an aqueous solution of one of the treating agents of the' invention. The photographic layer is allowed to remain in the bath until it has absorbed sufficient treating solution to inhibit discoloration. The photographic layer is then removed from the bath and allowed to dry containing the absorbed treating agent. Optionally, surplus treatingsolution may be rem moved from the surface of the photographic element or. layer by means of a squeegee, rapid Water rinse or other suitable means prior to drying. When a Water rinse is employed, however, care must be. taken not to remove absorbed treating agent from the treated layer.

As indicated above, my invention is particularly useful in stabilizing photographic color images produced by a reversal color process wherein the color-forming components or couplers are incorporated Within the photo graphic colo developer, One of the most common of these processes is known as the Kodachrome Process.

Especially useful color-formin compounds or couplers 7 Which can be incorporated in color developers include the following: 7

COUPLERS PRODUCING CYAN IMAGES l-naphthol-2-carboXylic-a-naphthalide l-uaphtho1-5sulfo-cyclohexy1amide S-phenoxyacetamino-l-naphthol 5-,8-phenylpropionylamino-l-naphthol Monochlor-S-(N-v-phenylpropyl-N-p-sec.-amylbenzoyl- 'amino)-l-naphtho1 V 2-acetylamino-5-methylphenol 2-benzoylamino-3,S-dimethylphenol 2-:1 (p-tert. amylphen'oxy)n-butyrylamino-S-methylphenol f 6-{ -{4- ['y- 2,4-di-tert. amylphenoXy) butyramido] phenoxy}acetamido}-2,4-dichloro-3-methylphenol l-hydroxy-Z- [6- 2,4-di-tert. amylphenoxy -n-but'yl] mph 7 tha'mide I 2-01 (p-tert; amylphenoxy) -n-butyrylamino-4-chlo'ro 5- methylphenol 2 (p-tert. amylphenoxy-p-benzoyl) amino-4 -chloro-5- methylphenol I 7 2-(4"-tert. a'myl-B'rphenoxybenzoylamino)-3,S-dimethyl l-phenol I Z-phenylacetylamino 4-chloro-S-methylphenol -2-benzoylamino-4-chloro-5 methylphenol in the art for protecting colored photographic elements against discoloration due to fading or print-out, none has proven to be a complete solution to the problem andthe search-for new methods has continued.

1. I The methods of the present invention for preventing the discoloration ofwater permeable photographic layers containing dye images comprise treating such layers with aqueous solutions of certain organic compounds in order to introduce sufficient quantitiesofthese treating agents 2-anilinoacetylamino-4-chloro-S-methyIphenOl a 1 2 {4'-[a-(4"-tert. amylphenoxy)-n'-butyrylamino]benzoylarnino}-4-chloro-5-rhethylphenol v v i 2-[4',3"-(4"-tert.amylphenoxy)benzoylamino]ben V zoylaminoi-chloro-5-rnethylphenol- I 2p-nitrobenz oylamino-4-chloro-5 methylphenol 2-rn-aminobenzoyl 4-chloro-5-methylphenol 2-acetaniino-4 -chloro-S-methylphenol 2{4-sec. amylbenzamino)-4-chl0ro-5 rnethylphenol I" 7 2(4-n-amyloxyhenzamino)-4-chloro-imethylphenol 2(4f-phenoxybenzoylamino}phenol are particularly useful.

that the nature of thejphotographic layer will have an out is not critical.

3 4,4'-di- (acetoacetamino )-3 SY-dimethyldigihenyl p,p-Diacetoacetamino) diphenylrnethane Ethyl-p-benzc ylacetaminobenzenesulfonate Nonyl-p-benzoylacetaminobenzenesulfonate N-phenyl l '-(p-acetoacetaminophenyl)urea n-Propyl-p-benzoy1acetaminobenzenesulfonate acetoacetpiperidine w-Benzoylacetpiperidide' 1 N(w-benzoylacetyl) 1,2,3,4-tetrahydroquinoline N(w-benzoylacetyl}morpholine in addition to the above couplers, couplers which are particularly useful in color developers include Couplers l64 listed in column 3-5 of Spath US. Patent 2,956,876, issued October 18, 1960.

The concentration of glucoheptonate in the aqueous treating solutions of the invention can range from a lower limit below which insufiicient treating agent is absorbed by the'treated photographic layer to provide a substantial increase in the stability of anydye image, or residual coupler therein, to an upper limit above which additional glucoheptonatehas little beneficial eifect. Most useful of treating agent by weight. The optimum concentration of the treating solution varies with the particular treating agent employed, and with the particular dyes and couplers treated, as Well as other factors. In general,

concentrations of treating agent from about 5 to 16% It should also be recognized effect upon the optimum concentration. For example, porous photographic elements such as photographic paper,

2 as opposed .to filrn, may. require larger amounts of treat ing agent for the same degree of stabilization.

'The temperature at which the treatments are carried As a matter of convenience, it may he desired to employ the treating solutions at room tem perature. It is, of course, important that the temperature of the treating solutions should not be high enough to damagethe photographic layer or element being treated, or to decompose or otherwise adversely effect the treating agent.

' The treating time required in the present invention varies with the permeability to thetreating solution of the photographic elements being treated. In general, a few-minutes immersion in, or contact with (e.g., spray- Sodium sulfate treating solutions contain from about 2 to about 20% The photographic element was then spray washed with water for about /2 minute and given an exposure to red illumination of 1100 ft. candle seconds. The exposed material was then developed in a cyan developer having the following formula: I

Carbohydrazide g' 3.2 Quadrafos u g;

Sodium bromide g 2.50 Potassium iodide (0.1% solution) "ml-.. 5.0

Sodium sulfite Sodium hydroxide 6-nitrobenzimida'zole (1% solution,

1% sodium hydroxide) a ml. p-N-benzylaminophenol g 0.70 Coupler 2 g 1.50 4-amino -N,N-diethyl-3-methylaniline Y hydrochloride g 2.60.

Water to one liter 1 Sodium tetraphosphate. 7 V F 2- (o-acetamido-d-phenylethyl)rl-hydroxy-naphthamide. As hydrochloride. 7 In place of the carbohydrazide, it was also found possible to use 4.7 g./liter of semicarbazide, 0.25 g./liter of .hydroxylamine sulfate orjCmZS g./liter of hydrazine sulfate.

The photographic element was thedwashed for about i /2 minute-with water and exposed to blue light 'of 301}.

ft. candle seconds intensity and developed in a yellow color developer containing a phenylenediamine colordeveloping agent, such as 4-aminol,N-diethylaniline hy-,

droch loride and a yellow coupler, such as Coupler" No. l 47 from column 4 of U.S. Patent 2,956,876. The photo graphic element was then washed and fogged chemically by treatment with a sodium borohydride solution, .as' described in l-lenn et al. US. Patent 2,984,567, iss ed" May 16, 1961. The photographic element was then developed in a magenta color developer containing a color developing agent, suchas 4-amino-N,N,-diejd1yl-3- methylanilinehydrochloride and a magenta coupler, such I as Coupler No. in column4 of US. Patent 2,956,876.

The photographic element, processed as described 7 above, was split in half andone-h'alf was then immersed ing, etc.), the treating bath is sufiicient in"most"cases,

although shorter or longer times mayoften be employed with success. It is, of course, essential that the photographic element be immersed long enough to absorb sufih cient treating agent to provide a significant improvement in the stability of the color element against discoloration.

The invention will now be described more specifically in the following example which has been selected for purposes of illustration only and is not to be construed as limiting the scope of the invention. 1

V 7 Example A multi-layer photographic element of the {type described in Mannes 'et al. US- Patent 2,252,718, issued August 19, 1941, was exposed to arr-original multi-colored scene and developed for about 3 /2 minutes at 86 F. in a developer having the tollowing composition:

.Water'to one liter V V V, Sodium tetraphosphate.tonhexarnetaphosphate). a

for one minute in a 5% aqueous solution (by weight) of sodium a-glucoheptonate dihydrate- The immersed strip was then removed from the solution, dipped once in wash water and dried at room temperature;

Each of the above strips was then given an exposure of 360,000 foot-candle-hours to tungsten illumination.-

Where the original densities hadbeen 1.0, the following density loss figures were obtainedfor the, strips after illumination: 1 V a a Red Green Blue Untreated Strip a r 0t) 7 36 V 31 Treated Strip .'02' -.19 17 In a similar manner, color prints of the kind. referred to in PrinciplesofColor Photography? by Evans, Han

. son and Brewer, 1953, page 307, prepared from 3 layers 7 of light-sensitive silver halide emulsion containing, ;respectively, prior tocolor development, color couplerspro 1'65 ducing yellow, magenta and cyan dye s, and coated on a paper support, Weretreated' with an aqueous solution containing 5% by Weight-of sodium c glucoheptonate 1 dihydratei After the prints werethus'treatejd,theywere squeeged and dried to produce printswhich showed un staining. 7, v

As indicated above, treatment of the processed photographic color elements should be made in such a manner that a significant quantity of the glucoheptonate remains in the finished photographic color element in order to secure the desired stabilization of the dye image, or residual coupler, if this remains in the element. The optional rapid water washing of the materials treated according to the invention, should be carried out in such a way that only surplus glucobeptonate is removed from the surface of the element, and a sufficient amount of this chemical remains within the finished photographic element.

The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can he efiected within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

What I claim as my invention and desire secured by Letters Patent of the United States is:

1. A method of inhibiting discoloration of a photographic element which has been exposed, processed to a photographic record comprising at least one dye image, and residual silver and silver salts removed from the element which comprises imbibing in said processed element and aqueous solution comprising a water-soluble glucoheptonate.

2. A method of stabilizing a photographic color element which has been processed to a visible record by a reversal processing technique wherein the color-forming components are incorporated Within a photographic color developer, and residual silver and silver halide are removed from the element, comprising imbibing in said completely processed photographic element an aqueous solution comprising a water-soluble glucoheptonate.

3. A process according to claim .2 wherein said glucoheptonate is an alkali metal salt of a-glucoheptonic acid;

4. A process according to claim 3 wherein said alkali metal salt is the sodium salt.

5. A method of stabilizing the dye image of a photographic element comprising a support and a plurality of photographic emulsion layers wherein said dye image comprises a dye selected from the class consisting of azomethine dyes, indoaniline dyes, indophenol dyes and indamine dyes, comprising dispersing throughout said dye image an aqueous solution containing a water-soluble glucoheptonate.

6. A process according to claim 5 wherein said glucoheptonate is an alkali metal salt of m-glucoheptonic acid.

7. A process according to claim 6 wherein said water-soluble salt is sodium a-glucoheptonate dihydrate.

References Cited in the file of this patent UNITED STATES PATENTS 2,214,216 Webster Sept. 10, 1940 2,384,663 Weissberger et al. Sept. 11, 1945 2,515,122 Harsh et al. July 11, 1950 2,543,181 Land Feb. 27, 1951 2,656,272 Gunther Oct. 20, 1953 2,852,372 Morse Sept. 16, 1958 

1. A METHOD OF INHIBITING DISCOLORATGION OF A PHOTOGRAPHIC ELEMENT WHICH HAS BEEN EXPOSED, PROCESSED TO A PHOTOGRAPHIC RECORD COMPRISING AT LEASTG ONE DYE IMAGE, AND RESIDUAL SILVER AND SILVER SALTS REMOVED FROM THE ELEMENT WHICH COMPRISES IMBIBING IN SAID PROCESSED ELEMENT AND AQUEOUS SOLUTION COMPRISING A WATER-SOLUBLE GLUCOHEPTONATE. 